One 8 count package of Lost Your Marbles. Lost your marbles? They were here a minute ago. Birthday Direct has found them. Each marble has a diameter of 0.5 inches and they are black in color. You cannot have an over the hill party without your lost marbles. This birthday party is going to be humorous and you are bound to have a great time. This is only one of the many Gag Birthday Gifts that Birthday Direct has to offer.